Bio-based sulfonated surfactants with high Ca²⁺ tolerance in detergent formulations

The use of calcium-resistant surfactants in household and industrial washing applications may simplify the formulation composition of laundry and therefore reduce costs. A series of bio-based surfactants, N-alkyl furfuryl methylamine sulfonates (AFMS), was developed from the biomass-derived furfural and aliphatic amines by a simple and effective method. The structure of these bio-based surfactants was characterized by gas chromatography–mass spectrometry, liquid chromatography–mass spectrometry and ¹H nuclear magnetic resonance spectroscopy. These bio-based surfactants demonstrated low surface tension, high emulsification, and high decontamination efficiency. Meanwhile, the AFMS surfactants exhibited excellent calcium resistance, maintaining micelle stability in Ca²⁺up to 2.16 × 10⁴ mg/L and the solution clarification in Ca²⁺up to 7.21 × 10⁴ mg/L. Furthermore, the AFMS surfactants had a stable decontamination effect in hard water. The wetting ability, foaming ability, toxicity, and biodegradability parameters were also evaluated. Therefore, the AFMS surfactants synthesized in this work could be applied as a more efficient and promising bio-based surfactant candidate for application in household and industrial washing.